Résumé
Sweet potatoes are cultivated across a wide range of subtropical and tropical regions due to their resilience to diverse environmental conditions. As a starch-rich crop, they serve as a staple food in many countries, typically consumed in forms such as purée or baked goods. Orange-fleshed sweet potato varieties are particularly valued for their high carotenoid content, which plays a crucial role in vitamin A supply. In this study, the roots of six yellow and orange-fleshed sweet potato cultivars were analyzed, revealing a broad spectrum of carotenoid levels, ranging from 1.0 to 62.2 mg β-carotene equivalents per 100g dry weight. The carotenoids were primarily composed of β-carotene, with smaller amounts of α-carotene, lutein, and β-carotene 5,8-epoxide.The impact of various cooking methods, both alone and in combination with lactic acid fermentation (LAF), on carotenoid content was investigated. Baking significantly reduced carotenoid levels, whereas boiling, frying, microwave cooking, and especially steaming preserved or even enhanced carotenoid content. The observed effects are likely due to plant cell lysis and enzyme inactivation during these cooking processes. LAF was applied either before or after cooking, using two different lactic acid bacterial strains. Unexpectedly, pre-cooking LAF led to a reduction in carotenoid levels, particularly after baking, with α-carotene being the most affected. In contrast, performing LAF post-cooking generally preserved carotenoid content. Steaming followed by LAF emerged as the most effective method for retaining carotenoids, especially β-carotene. All processing methods modified sweet potato flesh color, reducing L* (lightness) and a* (red component) values. Conversely, b* (yellow component) decreased with baking, both alone and in combination with LAF, as well as with steaming. However, b* increased when LAF was applied prior to cooking. This study provides insights into how processing techniques influence the retention of bioactive compounds in sweet potatoes.